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path: root/fs/btrfs/volumes.c (follow)
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2020-10-07btrfs: skip devices without magic signature when mountingAnand Jain1-6/+12
Many things can happen after the device is scanned and before the device is mounted. One such thing is losing the BTRFS_MAGIC on the device. If it happens we still won't free that device from the memory and cause the userland confusion. For example: As the BTRFS_IOC_DEV_INFO still carries the device path which does not have the BTRFS_MAGIC, 'btrfs fi show' still lists device which does not belong to the filesystem anymore: $ mkfs.btrfs -fq -draid1 -mraid1 /dev/sda /dev/sdb $ wipefs -a /dev/sdb # /dev/sdb does not contain magic signature $ mount -o degraded /dev/sda /btrfs $ btrfs fi show -m Label: none uuid: 470ec6fb-646b-4464-b3cb-df1b26c527bd Total devices 2 FS bytes used 128.00KiB devid 1 size 3.00GiB used 571.19MiB path /dev/sda devid 2 size 3.00GiB used 571.19MiB path /dev/sdb We need to distinguish the missing signature and invalid superblock, so add a specific error code ENODATA for that. This also fixes failure of fstest btrfs/198. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: return error if we're unable to read device statsJosef Bacik1-8/+18
I noticed when fixing device stats for seed devices that we simply threw away the return value from btrfs_search_slot(). This is because we may not have stat items, but we could very well get an error, and thus miss reporting the error up the chain. Fix this by returning ret if it's an actual error, and then stop trying to init the rest of the devices stats and return the error up the chain. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: init device stats for seed devicesJosef Bacik1-41/+46
We recently started recording device stats across the fleet, and noticed a large increase in messages such as this BTRFS warning (device dm-0): get dev_stats failed, not yet valid on our tiers that use seed devices for their root devices. This is because we do not initialize the device stats for any seed devices if we have a sprout device and mount using that sprout device. The basic steps for reproducing are: $ mkfs seed device $ mount seed device # fill seed device $ umount seed device $ btrfstune -S 1 seed device $ mount seed device $ btrfs device add -f sprout device /mnt/wherever $ umount /mnt/wherever $ mount sprout device /mnt/wherever $ btrfs device stats /mnt/wherever This will fail with the above message in dmesg. Fix this by iterating over the fs_devices->seed if they exist in btrfs_init_dev_stats. This fixed the problem and properly reports the stats for both devices. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ rename to btrfs_device_init_dev_stats ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: simplify gotos in open_seed_deviceAnand Jain1-5/+3
The function does not have a common exit block and returns immediatelly so there's no point having the goto. Remove the two cases. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: remove unnecessary tmp variable in btrfs_assign_next_active_device()Anand Jain1-6/+3
We can check the argument value directly, no need for the temporary variable. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: use sprout device_list_mutex in btrfs_init_devices_lateAnand Jain1-3/+1
On a mounted sprout filesystem, all threads now are using the sprout::device_list_mutex, and this is the only code using the seed::device_list_mutex. This patch converts to use the sprouts fs_info->fs_devices->device_list_mutex. The same reasoning holds true here, that device delete is holding the sprout::device_list_mutex. Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: split and refactor btrfs_sysfs_remove_devices_dirAnand Jain1-4/+4
Similar to btrfs_sysfs_add_devices_dir()'s refactoring, split btrfs_sysfs_remove_devices_dir() so that we don't have to use the device argument to indicate whether to free all devices or just one device. Export btrfs_sysfs_remove_device() as device operations outside of sysfs.c now calls this instead of btrfs_sysfs_remove_devices_dir(). btrfs_sysfs_remove_devices_dir() is renamed to btrfs_sysfs_remove_fs_devices() to suite its new role. Now, no one outside of sysfs.c calls btrfs_sysfs_remove_fs_devices() so it is redeclared s static. And the same function had to be moved before its first caller. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: simplify parameters of btrfs_sysfs_add_devices_dirAnand Jain1-1/+1
When we add a device we need to add it to sysfs, so instead of using the btrfs_sysfs_add_devices_dir() fs_devices argument to specify whether to add a device or all of fs_devices, call the helper function directly btrfs_sysfs_add_device() and thus make it non-static. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: improve device scanning messagesAnand Jain1-6/+8
Systems booting without the initramfs seems to scan an unusual kind of device path (/dev/root). And at a later time, the device is updated to the correct path. We generally print the process name and PID of the process scanning the device but we don't capture the same information if the device path is rescanned with a different pathname. The current message is too long, so drop the unnecessary UUID and add process name and PID. While at this also update the duplicate device warning to include the process name and PID so the messages are consistent CC: stable@vger.kernel.org # 4.19+ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=89721 Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: enumerate the type of exclusive operation in progressGoldwyn Rodrigues1-10/+10
Instead of using a flag bit for exclusive operation, use a variable to store which exclusive operation is being performed. Introduce an API to start and finish an exclusive operation. This would enable another way for tools to check which operation is running on why starting an exclusive operation failed. The followup patch adds a sysfs_notify() to alert userspace when the state changes, so userspace can perform select() on it to get notified of the change. This would enable us to enqueue a command which will wait for current exclusive operation to complete before issuing the next exclusive operation. This has been done synchronously as opposed to a background process, or else error collection (if any) will become difficult. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update comments ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: sysfs: init devices outside of the chunk_mutexJosef Bacik1-3/+4
While running btrfs/061, btrfs/073, btrfs/078, or btrfs/178 we hit the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc3+ #4 Not tainted ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff96ecc22ef4a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330 but task is already holding lock: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x65/0x80 slab_pre_alloc_hook.constprop.0+0x20/0x200 kmem_cache_alloc+0x37/0x270 alloc_inode+0x82/0xb0 iget_locked+0x10d/0x2c0 kernfs_get_inode+0x1b/0x130 kernfs_get_tree+0x136/0x240 sysfs_get_tree+0x16/0x40 vfs_get_tree+0x28/0xc0 path_mount+0x434/0xc00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (kernfs_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 kernfs_add_one+0x23/0x150 kernfs_create_link+0x63/0xa0 sysfs_do_create_link_sd+0x5e/0xd0 btrfs_sysfs_add_devices_dir+0x81/0x130 btrfs_init_new_device+0x67f/0x1250 btrfs_ioctl+0x1ef/0x2e20 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 btrfs_chunk_alloc+0x125/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_insert_empty_items+0x64/0xb0 btrfs_insert_delayed_items+0x90/0x4f0 btrfs_commit_inode_delayed_items+0x93/0x140 btrfs_log_inode+0x5de/0x2020 btrfs_log_inode_parent+0x429/0xc90 btrfs_log_new_name+0x95/0x9b btrfs_rename2+0xbb9/0x1800 vfs_rename+0x64f/0x9f0 do_renameat2+0x320/0x4e0 __x64_sys_rename+0x1f/0x30 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 __mutex_lock+0x7e/0x7e0 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 kthread+0x138/0x160 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> kernfs_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(kernfs_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/100: #0: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff8dd65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290 #2: ffff96ed2ade30e0 (&type->s_umount_key#36){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0 stack backtrace: CPU: 0 PID: 100 Comm: kswapd0 Not tainted 5.9.0-rc3+ #4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb8 check_noncircular+0x12d/0x150 __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 __mutex_lock+0x7e/0x7e0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? lock_acquire+0xa7/0x3d0 ? find_held_lock+0x2b/0x80 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 ? _raw_spin_unlock_irqrestore+0x41/0x50 ? add_wait_queue_exclusive+0x70/0x70 ? balance_pgdat+0x670/0x670 kthread+0x138/0x160 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 This happens because we are holding the chunk_mutex at the time of adding in a new device. However we only need to hold the device_list_mutex, as we're going to iterate over the fs_devices devices. Move the sysfs init stuff outside of the chunk_mutex to get rid of this lockdep splat. CC: stable@vger.kernel.org # 4.4.x: f3cd2c58110dad14e: btrfs: sysfs, rename device_link add/remove functions CC: stable@vger.kernel.org # 4.4.x Reported-by: David Sterba <dsterba@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: don't opencode sync_blockdev in btrfs_init_new_deviceNikolay Borisov1-1/+1
Instead of opencoding filemap_write_and_wait simply call syncblockdev as it makes it abundantly clear what's going on and why this is used. No semantics changes. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: remove redundant code from btrfs_free_stale_devicesNikolay Borisov1-2/+0
Following the refactor of btrfs_free_stale_devices in 7bcb8164ad94 ("btrfs: use device_list_mutex when removing stale devices") fs_devices are freed after they have been iterated by the inner list_for_each so the use-after-free fixed by introducing the break in fd649f10c3d2 ("btrfs: Fix use-after-free when cleaning up fs_devs with a single stale device") is no longer necessary. Just remove it altogether. No functional changes. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: refactor locked condition in btrfs_init_new_deviceNikolay Borisov1-3/+4
Invert unlocked to locked and exploit the fact it can only ever be modified if we are adding a new device to a seed filesystem. This allows to simplify the check in error: label. No semantics changes. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: use RCU for quick device check in btrfs_init_new_deviceNikolay Borisov1-5/+4
When adding a new device there's a mandatory check to see if a device is being duplicated to the filesystem it's added to. Since this is a read-only operations not necessary to take device_list_mutex and can simply make do with an rcu-readlock. Using just RCU is safe because there won't be another device add delete running in parallel as btrfs_init_new_device is called only from btrfs_ioctl_add_dev. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: do not hold device_list_mutex when closing devicesJosef Bacik1-5/+4
The following lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00169-g87212851a027-dirty #929 Not tainted ------------------------------------------------------ fsstress/8739 is trying to acquire lock: ffff88bfd0eb0c90 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x43/0x70 but task is already holding lock: ffff88bfbd16e538 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x6a/0x4a0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #10 (sb_pagefaults){.+.+}-{0:0}: __sb_start_write+0x129/0x210 btrfs_page_mkwrite+0x6a/0x4a0 do_page_mkwrite+0x4d/0xc0 handle_mm_fault+0x103c/0x1730 exc_page_fault+0x340/0x660 asm_exc_page_fault+0x1e/0x30 -> #9 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #8 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #7 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #6 (cpu_hotplug_lock){++++}-{0:0}: cpus_read_lock+0x39/0xb0 kmem_cache_create_usercopy+0x28/0x230 kmem_cache_create+0x12/0x20 bioset_init+0x15e/0x2b0 init_bio+0xa3/0xaa do_one_initcall+0x5a/0x2e0 kernel_init_freeable+0x1f4/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #5 (bio_slab_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 bioset_init+0xbc/0x2b0 __blk_alloc_queue+0x6f/0x2d0 blk_mq_init_queue_data+0x1b/0x70 loop_add+0x110/0x290 [loop] fq_codel_tcf_block+0x12/0x20 [sch_fq_codel] do_one_initcall+0x5a/0x2e0 do_init_module+0x5a/0x220 load_module+0x2459/0x26e0 __do_sys_finit_module+0xba/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (loop_ctl_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 lo_open+0x18/0x50 [loop] __blkdev_get+0xec/0x570 blkdev_get+0xe8/0x150 do_dentry_open+0x167/0x410 path_openat+0x7c9/0xa80 do_filp_open+0x93/0x100 do_sys_openat2+0x22a/0x2e0 do_sys_open+0x4b/0x80 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&bdev->bd_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 blkdev_put+0x1d/0x120 close_fs_devices.part.31+0x84/0x130 btrfs_close_devices+0x44/0xb0 close_ctree+0x296/0x2b2 generic_shutdown_super+0x69/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 file_update_time+0xc8/0x110 btrfs_page_mkwrite+0x10c/0x4a0 do_page_mkwrite+0x4d/0xc0 handle_mm_fault+0x103c/0x1730 exc_page_fault+0x340/0x660 asm_exc_page_fault+0x1e/0x30 other info that might help us debug this: Chain exists of: &fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults); lock(&mm->mmap_lock#2); lock(sb_pagefaults); lock(&fs_info->reloc_mutex); *** DEADLOCK *** 3 locks held by fsstress/8739: #0: ffff88bee66eeb68 (&mm->mmap_lock#2){++++}-{3:3}, at: exc_page_fault+0x173/0x660 #1: ffff88bfbd16e538 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x6a/0x4a0 #2: ffff88bfbd16e630 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3da/0x5d0 stack backtrace: CPU: 17 PID: 8739 Comm: fsstress Kdump: loaded Not tainted 5.8.0-rc7-00169-g87212851a027-dirty #929 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 ? btrfs_get_alloc_profile+0x150/0x210 lock_acquire+0x9e/0x360 ? btrfs_record_root_in_trans+0x43/0x70 __mutex_lock+0x9f/0x930 ? btrfs_record_root_in_trans+0x43/0x70 ? lock_acquire+0x9e/0x360 ? join_transaction+0x5d/0x450 ? find_held_lock+0x2d/0x90 ? btrfs_record_root_in_trans+0x43/0x70 ? join_transaction+0x3d5/0x450 ? btrfs_record_root_in_trans+0x43/0x70 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 file_update_time+0xc8/0x110 btrfs_page_mkwrite+0x10c/0x4a0 ? handle_mm_fault+0x5e/0x1730 do_page_mkwrite+0x4d/0xc0 ? __do_fault+0x32/0x150 handle_mm_fault+0x103c/0x1730 exc_page_fault+0x340/0x660 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x7faa6c9969c4 Was seen in testing. The fix is similar to that of btrfs: open device without device_list_mutex where we're holding the device_list_mutex and then grab the bd_mutex, which pulls in a bunch of dependencies under the bd_mutex. We only ever call btrfs_close_devices() on mount failure or unmount, so we're save to not have the device_list_mutex here. We're already holding the uuid_mutex which keeps us safe from any external modification of the fs_devices. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locksJosef Bacik1-1/+0
When closing and freeing the source device we could end up doing our final blkdev_put() on the bdev, which will grab the bd_mutex. As such we want to be holding as few locks as possible, so move this call outside of the dev_replace->lock_finishing_cancel_unmount lock. Since we're modifying the fs_devices we need to make sure we're holding the uuid_mutex here, so take that as well. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: remove alloc_list splice in btrfs_prepare_sproutNikolay Borisov1-4/+0
btrfs_prepare_sprout is called when the first rw device is added to a seed filesystem. This means the filesystem can't have its alloc_list be non-empty, since seed filesystems are read only. Simply remove the code altogether. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: document some invariants of seed codeNikolay Borisov1-0/+15
Without good understanding of how seed devices works it's hard to grok some of what the code in open_seed_devices or btrfs_prepare_sprout does. Add comments hopefully reducing some of the cognitive load. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: switch seed device to list apiNikolay Borisov1-55/+48
While this patch touches a bunch of files the conversion is straighforward. Instead of using the implicit linked list anchored at btrfs_fs_devices::seed the code is switched to using list_for_each_entry. Previous patches in the series already factored out code that processed both main and seed devices so in those cases the factored out functions are called on the main fs_devices and then on every seed dev inside list_for_each_entry. Using list api also allows to simplify deletion from the seed dev list performed in btrfs_rm_device and btrfs_rm_dev_replace_free_srcdev by substituting a while() loop with a simple list_del_init. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: simplify setting/clearing fs_info to btrfs_fs_devicesNikolay Borisov1-18/+2
It makes no sense to have sysfs-related routines be responsible for properly initialising the fs_info pointer of struct btrfs_fs_device. Instead this can be streamlined by making it the responsibility of btrfs_init_devices_late to initialize it. That function already initializes fs_info of every individual device in btrfs_fs_devices. As far as clearing it is concerned it makes sense to move it to close_fs_devices. That function is only called when struct btrfs_fs_devices is no longer in use - either for holding seeds or main devices for a mounted filesystem. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: make close_fs_devices return voidNikolay Borisov1-8/+4
The return value of this function conveys absolutely no information. All callers already check the state of fs_devices->opened to decide how to proceed. So convert the function to returning void. While at it make btrfs_close_devices also return void. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: factor out loop logic from btrfs_free_extra_devidsNikolay Borisov1-14/+20
This prepares the code to switching seeds devices to a proper list. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: add owner and fs_info to alloc_state io_treeQu Wenruo1-3/+4
Commit 1c11b63eff2a ("btrfs: replace pending/pinned chunks lists with io tree") introduced btrfs_device::alloc_state extent io tree, but it doesn't initialize the fs_info and owner member. This means the following features are not properly supported: - Fs owner report for insert_state() error Without fs_info initialized, although btrfs_err() won't panic, it won't output which fs is causing the error. - Wrong owner for trace events alloc_state will get the owner as pinned extents. Fix this by assiging proper fs_info and owner for btrfs_device::alloc_state. Fixes: 1c11b63eff2a ("btrfs: replace pending/pinned chunks lists with io tree") Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: remove fsid argument from btrfs_sysfs_update_sprout_fsidNikolay Borisov1-2/+5
It can be accessed from 'fs_devices' as it's identical to fs_info->fs_devices. Also add a comment about why we are calling the function. No semantic changes. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-30btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locksJosef Bacik1-0/+3
When closing and freeing the source device we could end up doing our final blkdev_put() on the bdev, which will grab the bd_mutex. As such we want to be holding as few locks as possible, so move this call outside of the dev_replace->lock_finishing_cancel_unmount lock. Since we're modifying the fs_devices we need to make sure we're holding the uuid_mutex here, so take that as well. There's a report from syzbot probably hitting one of the cases where the bd_mutex and device_list_mutex are taken in the wrong order, however it's not with device replace, like this patch fixes. As there's no reproducer available so far, we can't verify the fix. https://lore.kernel.org/lkml/000000000000fc04d105afcf86d7@google.com/ dashboard link: https://syzkaller.appspot.com/bug?extid=84a0634dc5d21d488419 WARNING: possible circular locking dependency detected 5.9.0-rc5-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/6878 is trying to acquire lock: ffff88804c17d780 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x30/0x520 fs/block_dev.c:1804 but task is already holding lock: ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 btrfs_finish_chunk_alloc+0x281/0xf90 fs/btrfs/volumes.c:5255 btrfs_create_pending_block_groups+0x2f3/0x700 fs/btrfs/block-group.c:2109 __btrfs_end_transaction+0xf5/0x690 fs/btrfs/transaction.c:916 find_free_extent_update_loop fs/btrfs/extent-tree.c:3807 [inline] find_free_extent+0x23b7/0x2e60 fs/btrfs/extent-tree.c:4127 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370 do_writepages+0xec/0x290 mm/page-writeback.c:2352 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894 wb_do_writeback fs/fs-writeback.c:2039 [inline] wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 -> #3 (sb_internal#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write+0x234/0x470 fs/super.c:1672 sb_start_intwrite include/linux/fs.h:1690 [inline] start_transaction+0xbe7/0x1170 fs/btrfs/transaction.c:624 find_free_extent_update_loop fs/btrfs/extent-tree.c:3789 [inline] find_free_extent+0x25e1/0x2e60 fs/btrfs/extent-tree.c:4127 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370 do_writepages+0xec/0x290 mm/page-writeback.c:2352 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894 wb_do_writeback fs/fs-writeback.c:2039 [inline] wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 -> #2 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}: __flush_work+0x60e/0xac0 kernel/workqueue.c:3041 wb_shutdown+0x180/0x220 mm/backing-dev.c:355 bdi_unregister+0x174/0x590 mm/backing-dev.c:872 del_gendisk+0x820/0xa10 block/genhd.c:933 loop_remove drivers/block/loop.c:2192 [inline] loop_control_ioctl drivers/block/loop.c:2291 [inline] loop_control_ioctl+0x3b1/0x480 drivers/block/loop.c:2257 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (loop_ctl_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 lo_open+0x19/0xd0 drivers/block/loop.c:1893 __blkdev_get+0x759/0x1aa0 fs/block_dev.c:1507 blkdev_get fs/block_dev.c:1639 [inline] blkdev_open+0x227/0x300 fs/block_dev.c:1753 do_dentry_open+0x4b9/0x11b0 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x1b9a/0x2730 fs/namei.c:3368 do_filp_open+0x17e/0x3c0 fs/namei.c:3395 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1188 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&bdev->bd_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain kernel/locking/lockdep.c:3218 [inline] __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 blkdev_put+0x30/0x520 fs/block_dev.c:1804 btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline] btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline] btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline] close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161 close_fs_devices fs/btrfs/volumes.c:1193 [inline] btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179 close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149 generic_shutdown_super+0x144/0x370 fs/super.c:464 kill_anon_super+0x36/0x60 fs/super.c:1108 btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265 deactivate_locked_super+0x94/0x160 fs/super.c:335 deactivate_super+0xad/0xd0 fs/super.c:366 cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118 task_work_run+0xdd/0x190 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:163 [inline] exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &bdev->bd_mutex --> sb_internal#2 --> &fs_devs->device_list_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_devs->device_list_mutex); lock(sb_internal#2); lock(&fs_devs->device_list_mutex); lock(&bdev->bd_mutex); *** DEADLOCK *** 3 locks held by syz-executor.0/6878: #0: ffff88809070c0e0 (&type->s_umount_key#70){++++}-{3:3}, at: deactivate_super+0xa5/0xd0 fs/super.c:365 #1: ffffffff8a5b37a8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_close_devices+0x23/0x1f0 fs/btrfs/volumes.c:1178 #2: ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159 stack backtrace: CPU: 0 PID: 6878 Comm: syz-executor.0 Not tainted 5.9.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827 check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain kernel/locking/lockdep.c:3218 [inline] __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 blkdev_put+0x30/0x520 fs/block_dev.c:1804 btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline] btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline] btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline] close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161 close_fs_devices fs/btrfs/volumes.c:1193 [inline] btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179 close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149 generic_shutdown_super+0x144/0x370 fs/super.c:464 kill_anon_super+0x36/0x60 fs/super.c:1108 btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265 deactivate_locked_super+0x94/0x160 fs/super.c:335 deactivate_super+0xad/0xd0 fs/super.c:366 cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118 task_work_run+0xdd/0x190 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:163 [inline] exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460027 RSP: 002b:00007fff59216328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000076035 RCX: 0000000000460027 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fff592163d0 RBP: 0000000000000333 R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000246 R12: 00007fff59217460 R13: 0000000002df2a60 R14: 0000000000000000 R15: 00007fff59217460 Signed-off-by: Josef Bacik <josef@toxicpanda.com> [ add syzbot reference ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-25btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishingJosef Bacik1-9/+3
We need to move the closing of the src_device out of all the device replace locking, but we definitely want to zero out the superblock before we commit the last time to make sure the device is properly removed. Handle this by pushing btrfs_scratch_superblocks into btrfs_dev_replace_finishing, and then later on we'll move the src_device closing and freeing stuff where we need it to be. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07btrfs: fix lockdep splat in add_missing_devJosef Bacik1-0/+10
Nikolay reported a lockdep splat in generic/476 that I could reproduce with btrfs/187. ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc2+ #1 Tainted: G W ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff9e8ef38b6268 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330 but task is already holding lock: ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x65/0x80 slab_pre_alloc_hook.constprop.0+0x20/0x200 kmem_cache_alloc_trace+0x3a/0x1a0 btrfs_alloc_device+0x43/0x210 add_missing_dev+0x20/0x90 read_one_chunk+0x301/0x430 btrfs_read_sys_array+0x17b/0x1b0 open_ctree+0xa62/0x1896 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x379 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 path_mount+0x434/0xc00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 btrfs_chunk_alloc+0x125/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_lookup_inode+0x2a/0x8f __btrfs_update_delayed_inode+0x80/0x240 btrfs_commit_inode_delayed_inode+0x119/0x120 btrfs_evict_inode+0x357/0x500 evict+0xcf/0x1f0 vfs_rmdir.part.0+0x149/0x160 do_rmdir+0x136/0x1a0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: __lock_acquire+0x1184/0x1fa0 lock_acquire+0xa4/0x3d0 __mutex_lock+0x7e/0x7e0 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 kthread+0x138/0x160 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&fs_info->chunk_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/100: #0: ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffffa9d65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290 #2: ffff9e8e9da260e0 (&type->s_umount_key#48){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0 stack backtrace: CPU: 1 PID: 100 Comm: kswapd0 Tainted: G W 5.9.0-rc2+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x92/0xc8 check_noncircular+0x12d/0x150 __lock_acquire+0x1184/0x1fa0 lock_acquire+0xa4/0x3d0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 __mutex_lock+0x7e/0x7e0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? lock_acquire+0xa4/0x3d0 ? btrfs_evict_inode+0x11e/0x500 ? find_held_lock+0x2b/0x80 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 ? _raw_spin_unlock_irqrestore+0x46/0x60 ? add_wait_queue_exclusive+0x70/0x70 ? balance_pgdat+0x670/0x670 kthread+0x138/0x160 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 This is because we are holding the chunk_mutex when we call btrfs_alloc_device, which does a GFP_KERNEL allocation. We don't want to switch that to a GFP_NOFS lock because this is the only place where it matters. So instead use memalloc_nofs_save() around the allocation in order to avoid the lockdep splat. Reported-by: Nikolay Borisov <nborisov@suse.com> CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27btrfs: drop path before adding new uuid tree entryJosef Bacik1-1/+2
With the conversion of the tree locks to rwsem I got the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925 Not tainted ------------------------------------------------------ btrfs-uuid/7955 is trying to acquire lock: ffff88bfbafec0f8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 but task is already holding lock: ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (btrfs-uuid-00){++++}-{3:3}: down_read_nested+0x3e/0x140 __btrfs_tree_read_lock+0x39/0x180 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x4bd/0x990 btrfs_uuid_tree_add+0x89/0x2d0 btrfs_uuid_scan_kthread+0x330/0x390 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 -> #0 (btrfs-root-00){++++}-{3:3}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 down_read_nested+0x3e/0x140 __btrfs_tree_read_lock+0x39/0x180 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x4bd/0x990 btrfs_find_root+0x45/0x1b0 btrfs_read_tree_root+0x61/0x100 btrfs_get_root_ref.part.50+0x143/0x630 btrfs_uuid_tree_iterate+0x207/0x314 btrfs_uuid_rescan_kthread+0x12/0x50 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-uuid-00); lock(btrfs-root-00); lock(btrfs-uuid-00); lock(btrfs-root-00); *** DEADLOCK *** 1 lock held by btrfs-uuid/7955: #0: ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 stack backtrace: CPU: 73 PID: 7955 Comm: btrfs-uuid Kdump: loaded Not tainted 5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? __btrfs_tree_read_lock+0x39/0x180 ? btrfs_root_node+0x1c/0x1d0 down_read_nested+0x3e/0x140 ? __btrfs_tree_read_lock+0x39/0x180 __btrfs_tree_read_lock+0x39/0x180 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x4bd/0x990 btrfs_find_root+0x45/0x1b0 btrfs_read_tree_root+0x61/0x100 btrfs_get_root_ref.part.50+0x143/0x630 btrfs_uuid_tree_iterate+0x207/0x314 ? btree_readpage+0x20/0x20 btrfs_uuid_rescan_kthread+0x12/0x50 kthread+0x133/0x150 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x1f/0x30 This problem exists because we have two different rescan threads, btrfs_uuid_scan_kthread which creates the uuid tree, and btrfs_uuid_tree_iterate that goes through and updates or deletes any out of date roots. The problem is they both do things in different order. btrfs_uuid_scan_kthread() reads the tree_root, and then inserts entries into the uuid_root. btrfs_uuid_tree_iterate() scans the uuid_root, but then does a btrfs_get_fs_root() which can read from the tree_root. It's actually easy enough to not be holding the path in btrfs_uuid_scan_kthread() when we add a uuid entry, as we already drop it further down and re-start the search when we loop. So simply move the path release before we add our entry to the uuid tree. This also fixes a problem where we're holding a path open after we do btrfs_end_transaction(), which has it's own problems. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-12btrfs: trim: fix underflow in trim length to prevent access beyond device boundaryQu Wenruo1-0/+4
[BUG] The following script can lead to tons of beyond device boundary access: mkfs.btrfs -f $dev -b 10G mount $dev $mnt trimfs $mnt btrfs filesystem resize 1:-1G $mnt trimfs $mnt [CAUSE] Since commit 929be17a9b49 ("btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit"), we try to avoid trimming ranges that's already trimmed. So we check device->alloc_state by finding the first range which doesn't have CHUNK_TRIMMED and CHUNK_ALLOCATED not set. But if we shrunk the device, that bits are not cleared, thus we could easily got a range starts beyond the shrunk device size. This results the returned @start and @end are all beyond device size, then we call "end = min(end, device->total_bytes -1);" making @end smaller than device size. Then finally we goes "len = end - start + 1", totally underflow the result, and lead to the beyond-device-boundary access. [FIX] This patch will fix the problem in two ways: - Clear CHUNK_TRIMMED | CHUNK_ALLOCATED bits when shrinking device This is the root fix - Add extra safety check when trimming free device extents We check and warn if the returned range is already beyond current device. Link: https://github.com/kdave/btrfs-progs/issues/282 Fixes: 929be17a9b49 ("btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit") CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: move the chunk_mutex in btrfs_read_chunk_treeJosef Bacik1-2/+2
We are currently getting this lockdep splat in btrfs/161: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc5+ #20 Tainted: G E ------------------------------------------------------ mount/678048 is trying to acquire lock: ffff9b769f15b6e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: clone_fs_devices+0x4d/0x170 [btrfs] but task is already holding lock: ffff9b76abdb08d0 (&fs_info->chunk_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x6a/0x800 [btrfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x8b/0x8f0 btrfs_init_new_device+0x2d2/0x1240 [btrfs] btrfs_ioctl+0x1de/0x2d20 [btrfs] ksys_ioctl+0x87/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __lock_acquire+0x1240/0x2460 lock_acquire+0xab/0x360 __mutex_lock+0x8b/0x8f0 clone_fs_devices+0x4d/0x170 [btrfs] btrfs_read_chunk_tree+0x330/0x800 [btrfs] open_ctree+0xb7c/0x18ce [btrfs] btrfs_mount_root.cold+0x13/0xfa [btrfs] legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 btrfs_mount+0x13b/0x3e0 [btrfs] legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 do_mount+0x7de/0xb30 __x64_sys_mount+0x8e/0xd0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->chunk_mutex); lock(&fs_devs->device_list_mutex); lock(&fs_info->chunk_mutex); lock(&fs_devs->device_list_mutex); *** DEADLOCK *** 3 locks held by mount/678048: #0: ffff9b75ff5fb0e0 (&type->s_umount_key#63/1){+.+.}-{3:3}, at: alloc_super+0xb5/0x380 #1: ffffffffc0c2fbc8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x54/0x800 [btrfs] #2: ffff9b76abdb08d0 (&fs_info->chunk_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x6a/0x800 [btrfs] stack backtrace: CPU: 2 PID: 678048 Comm: mount Tainted: G E 5.8.0-rc5+ #20 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./890FX Deluxe5, BIOS P1.40 05/03/2011 Call Trace: dump_stack+0x96/0xd0 check_noncircular+0x162/0x180 __lock_acquire+0x1240/0x2460 ? asm_sysvec_apic_timer_interrupt+0x12/0x20 lock_acquire+0xab/0x360 ? clone_fs_devices+0x4d/0x170 [btrfs] __mutex_lock+0x8b/0x8f0 ? clone_fs_devices+0x4d/0x170 [btrfs] ? rcu_read_lock_sched_held+0x52/0x60 ? cpumask_next+0x16/0x20 ? module_assert_mutex_or_preempt+0x14/0x40 ? __module_address+0x28/0xf0 ? clone_fs_devices+0x4d/0x170 [btrfs] ? static_obj+0x4f/0x60 ? lockdep_init_map_waits+0x43/0x200 ? clone_fs_devices+0x4d/0x170 [btrfs] clone_fs_devices+0x4d/0x170 [btrfs] btrfs_read_chunk_tree+0x330/0x800 [btrfs] open_ctree+0xb7c/0x18ce [btrfs] ? super_setup_bdi_name+0x79/0xd0 btrfs_mount_root.cold+0x13/0xfa [btrfs] ? vfs_parse_fs_string+0x84/0xb0 ? rcu_read_lock_sched_held+0x52/0x60 ? kfree+0x2b5/0x310 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 btrfs_mount+0x13b/0x3e0 [btrfs] ? cred_has_capability+0x7c/0x120 ? rcu_read_lock_sched_held+0x52/0x60 ? legacy_get_tree+0x30/0x50 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 do_mount+0x7de/0xb30 ? memdup_user+0x4e/0x90 __x64_sys_mount+0x8e/0xd0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is because btrfs_read_chunk_tree() can come upon DEV_EXTENT's and then read the device, which takes the device_list_mutex. The device_list_mutex needs to be taken before the chunk_mutex, so this is a problem. We only really need the chunk mutex around adding the chunk, so move the mutex around read_one_chunk. An argument could be made that we don't even need the chunk_mutex here as it's during mount, and we are protected by various other locks. However we already have special rules for ->device_list_mutex, and I'd rather not have another special case for ->chunk_mutex. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: open device without device_list_mutexJosef Bacik1-3/+18
There's long existed a lockdep splat because we open our bdev's under the ->device_list_mutex at mount time, which acquires the bd_mutex. Usually this goes unnoticed, but if you do loopback devices at all suddenly the bd_mutex comes with a whole host of other dependencies, which results in the splat when you mount a btrfs file system. ====================================================== WARNING: possible circular locking dependency detected 5.8.0-0.rc3.1.fc33.x86_64+debug #1 Not tainted ------------------------------------------------------ systemd-journal/509 is trying to acquire lock: ffff970831f84db0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x44/0x70 [btrfs] but task is already holding lock: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (sb_pagefaults){.+.+}-{0:0}: __sb_start_write+0x13e/0x220 btrfs_page_mkwrite+0x59/0x560 [btrfs] do_page_mkwrite+0x4f/0x130 do_wp_page+0x3b0/0x4f0 handle_mm_fault+0xf47/0x1850 do_user_addr_fault+0x1fc/0x4b0 exc_page_fault+0x88/0x300 asm_exc_page_fault+0x1e/0x30 -> #5 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x60/0x80 _copy_from_user+0x20/0xb0 get_sg_io_hdr+0x9a/0xb0 scsi_cmd_ioctl+0x1ea/0x2f0 cdrom_ioctl+0x3c/0x12b4 sr_block_ioctl+0xa4/0xd0 block_ioctl+0x3f/0x50 ksys_ioctl+0x82/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&cd->lock){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 sr_block_open+0xa2/0x180 __blkdev_get+0xdd/0x550 blkdev_get+0x38/0x150 do_dentry_open+0x16b/0x3e0 path_openat+0x3c9/0xa00 do_filp_open+0x75/0x100 do_sys_openat2+0x8a/0x140 __x64_sys_openat+0x46/0x70 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&bdev->bd_mutex){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 __blkdev_get+0x6a/0x550 blkdev_get+0x85/0x150 blkdev_get_by_path+0x2c/0x70 btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs] open_fs_devices+0x88/0x240 [btrfs] btrfs_open_devices+0x92/0xa0 [btrfs] btrfs_mount_root+0x250/0x490 [btrfs] legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x119/0x380 [btrfs] legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 do_mount+0x8c6/0xca0 __x64_sys_mount+0x8e/0xd0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 btrfs_run_dev_stats+0x36/0x420 [btrfs] commit_cowonly_roots+0x91/0x2d0 [btrfs] btrfs_commit_transaction+0x4e6/0x9f0 [btrfs] btrfs_sync_file+0x38a/0x480 [btrfs] __x64_sys_fdatasync+0x47/0x80 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 btrfs_commit_transaction+0x48e/0x9f0 [btrfs] btrfs_sync_file+0x38a/0x480 [btrfs] __x64_sys_fdatasync+0x47/0x80 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}: __lock_acquire+0x1241/0x20c0 lock_acquire+0xb0/0x400 __mutex_lock+0x7b/0x820 btrfs_record_root_in_trans+0x44/0x70 [btrfs] start_transaction+0xd2/0x500 [btrfs] btrfs_dirty_inode+0x44/0xd0 [btrfs] file_update_time+0xc6/0x120 btrfs_page_mkwrite+0xda/0x560 [btrfs] do_page_mkwrite+0x4f/0x130 do_wp_page+0x3b0/0x4f0 handle_mm_fault+0xf47/0x1850 do_user_addr_fault+0x1fc/0x4b0 exc_page_fault+0x88/0x300 asm_exc_page_fault+0x1e/0x30 other info that might help us debug this: Chain exists of: &fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults); lock(&mm->mmap_lock#2); lock(sb_pagefaults); lock(&fs_info->reloc_mutex); *** DEADLOCK *** 3 locks held by systemd-journal/509: #0: ffff97083bdec8b8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x12e/0x4b0 #1: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs] #2: ffff97083144d6a8 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3f8/0x500 [btrfs] stack backtrace: CPU: 0 PID: 509 Comm: systemd-journal Not tainted 5.8.0-0.rc3.1.fc33.x86_64+debug #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack+0x92/0xc8 check_noncircular+0x134/0x150 __lock_acquire+0x1241/0x20c0 lock_acquire+0xb0/0x400 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs] ? lock_acquire+0xb0/0x400 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs] __mutex_lock+0x7b/0x820 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs] ? kvm_sched_clock_read+0x14/0x30 ? sched_clock+0x5/0x10 ? sched_clock_cpu+0xc/0xb0 btrfs_record_root_in_trans+0x44/0x70 [btrfs] start_transaction+0xd2/0x500 [btrfs] btrfs_dirty_inode+0x44/0xd0 [btrfs] file_update_time+0xc6/0x120 btrfs_page_mkwrite+0xda/0x560 [btrfs] ? sched_clock+0x5/0x10 do_page_mkwrite+0x4f/0x130 do_wp_page+0x3b0/0x4f0 handle_mm_fault+0xf47/0x1850 do_user_addr_fault+0x1fc/0x4b0 exc_page_fault+0x88/0x300 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x7fa3972fdbfe Code: Bad RIP value. Fix this by not holding the ->device_list_mutex at this point. The device_list_mutex exists to protect us from modifying the device list while the file system is running. However it can also be modified by doing a scan on a device. But this action is specifically protected by the uuid_mutex, which we are holding here. We cannot race with opening at this point because we have the ->s_mount lock held during the mount. Not having the ->device_list_mutex here is perfectly safe as we're not going to change the devices at this point. CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add some comments ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: relocation: review the call sites which can be interrupted by signalQu Wenruo1-1/+16
Since most metadata reservation calls can return -EINTR when get interrupted by fatal signal, we need to review the all the metadata reservation call sites. In relocation code, the metadata reservation happens in the following sites: - btrfs_block_rsv_refill() in merge_reloc_root() merge_reloc_root() is a pretty critical section, we don't want to be interrupted by signal, so change the flush status to BTRFS_RESERVE_FLUSH_LIMIT, so it won't get interrupted by signal. Since such change can be ENPSPC-prone, also shrink the amount of metadata to reserve least amount avoid deadly ENOSPC there. - btrfs_block_rsv_refill() in reserve_metadata_space() It calls with BTRFS_RESERVE_FLUSH_LIMIT, which won't get interrupted by signal. - btrfs_block_rsv_refill() in prepare_to_relocate() - btrfs_block_rsv_add() in prepare_to_relocate() - btrfs_block_rsv_refill() in relocate_block_group() - btrfs_delalloc_reserve_metadata() in relocate_file_extent_cluster() - btrfs_start_transaction() in relocate_block_group() - btrfs_start_transaction() in create_reloc_inode() Can be interrupted by fatal signal and we can handle it easily. For these call sites, just catch the -EINTR value in btrfs_balance() and count them as canceled. CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: prefetch chunk tree leaves at mountDavid Sterba1-0/+27
The whole chunk tree is read at mount time so we can utilize readahead to get the tree blocks to memory before we read the items. The idea is from Robbie, but instead of updating search slot readahead, this patch implements the chunk tree readahead manually from nodes on level 1. We've decided to do specific readahead optimizations and then unify them under a common API so we don't break everything by changing the search slot readahead logic. Higher chunk trees grow on large filesystems (many terabytes), and prefetching just level 1 seems to be sufficient. Provided example was from a 200TiB filesystem with chunk tree level 2. CC: Robbie Ko <robbieko@synology.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: always initialize btrfs_bio::tgtdev_map/raid_map pointersNikolay Borisov1-20/+11
Since btrfs_bio always contains the extra space for the tgtdev_map and raid_maps it's pointless to make the assignment iff specific conditions are met. Instead, always assign the pointers to their correct value at allocation time. To accommodate this change also move code a bit in __btrfs_map_block so that btrfs_bio::stripes array is always initialized before the raid_map, subsequently move the call to sort_parity_stripes in the 'if' building the raid_map, retaining the old behavior. To better understand the change, there are 2 aspects to this: 1. The original code is harder to grasp because the calculations for initializing raid_map/tgtdev ponters are apart from the initial allocation of memory. Having them predicated on 2 separate checks doesn't help that either... So by moving the initialisation in alloc_btrfs_bio puts everything together. 2. tgtdev/raid_maps are now always initialized despite sometimes they might be equal i.e __btrfs_map_block_for_discard calls alloc_btrfs_bio with tgtdev = 0 but their usage should be predicated on external checks i.e. just because those pointers are non-null doesn't mean they are valid per-se. And actually while taking another look at __btrfs_map_block I saw a discrepancy: Original code initialised tgtdev_map if the following check is true: if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL) However, further down tgtdev_map is only used if the following check is true: if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL && need_full_stripe(op)) e.g. the additional need_full_stripe(op) predicate is there. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ copy more details from mail discussion ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: don't check for btrfs_device::bdev in btrfs_end_bioNikolay Borisov1-8/+7
btrfs_map_bio ensures that all submitted bios to devices have valid btrfs_device::bdev so this check can be removed from btrfs_end_bio. This check was added in june 2012 597a60fadedf ("Btrfs: don't count I/O statistic read errors for missing devices") but then in October of the same year another commit de1ee92ac3bc ("Btrfs: recheck bio against block device when we map the bio") started checking for the presence of btrfs_device::bdev before actually issuing the bio. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: record btrfs_device directly in btrfs_io_bioNikolay Borisov1-10/+4
Instead of recording stripe_index and using that to access correct btrfs_device from btrfs_bio::stripes record the btrfs_device in btrfs_io_bio. This will enable endio handlers to increment device error counters on checksum errors. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: allow use of global block reserve for balance item deletionDavid Sterba1-1/+1
On a filesystem with exhausted metadata, but still enough to start balance, it's possible to hit this error: [324402.053842] BTRFS info (device loop0): 1 enospc errors during balance [324402.060769] BTRFS info (device loop0): balance: ended with status: -28 [324402.172295] BTRFS: error (device loop0) in reset_balance_state:3321: errno=-28 No space left It fails inside reset_balance_state and turns the filesystem to read-only, which is unnecessary and should be fixed too, but the problem is caused by lack for space when the balance item is deleted. This is a one-time operation and from the same rank as unlink that is allowed to use the global block reserve. So do the same for the balance item. Status of the filesystem (100GiB) just after the balance fails: $ btrfs fi df mnt Data, single: total=80.01GiB, used=38.58GiB System, single: total=4.00MiB, used=16.00KiB Metadata, single: total=19.99GiB, used=19.48GiB GlobalReserve, single: total=512.00MiB, used=50.11MiB CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-21btrfs: fix mount failure caused by race with umountBoris Burkov1-0/+8
It is possible to cause a btrfs mount to fail by racing it with a slow umount. The crux of the sequence is generic_shutdown_super not yet calling sop->put_super before btrfs_mount_root calls btrfs_open_devices. If that occurs, btrfs_open_devices will decide the opened counter is non-zero, increment it, and skip resetting fs_devices->total_rw_bytes to 0. From here, mount will call sget which will result in grab_super trying to take the super block umount semaphore. That semaphore will be held by the slow umount, so mount will block. Before up-ing the semaphore, umount will delete the super block, resulting in mount's sget reliably allocating a new one, which causes the mount path to dutifully fill it out, and increment total_rw_bytes a second time, which causes the mount to fail, as we see double the expected bytes. Here is the sequence laid out in greater detail: CPU0 CPU1 down_write sb->s_umount btrfs_kill_super kill_anon_super(sb) generic_shutdown_super(sb); shrink_dcache_for_umount(sb); sync_filesystem(sb); evict_inodes(sb); // SLOW btrfs_mount_root btrfs_scan_one_device fs_devices = device->fs_devices fs_info->fs_devices = fs_devices // fs_devices-opened makes this a no-op btrfs_open_devices(fs_devices, mode, fs_type) s = sget(fs_type, test, set, flags, fs_info); find sb in s_instances grab_super(sb); down_write(&s->s_umount); // blocks sop->put_super(sb) // sb->fs_devices->opened == 2; no-op spin_lock(&sb_lock); hlist_del_init(&sb->s_instances); spin_unlock(&sb_lock); up_write(&sb->s_umount); return 0; retry lookup don't find sb in s_instances (deleted by CPU0) s = alloc_super return s; btrfs_fill_super(s, fs_devices, data) open_ctree // fs_devices total_rw_bytes improperly set! btrfs_read_chunk_tree read_one_dev // increment total_rw_bytes again!! super_total_bytes < fs_devices->total_rw_bytes // ERROR!!! To fix this, we clear total_rw_bytes from within btrfs_read_chunk_tree before the calls to read_one_dev, while holding the sb umount semaphore and the uuid mutex. To reproduce, it is sufficient to dirty a decent number of inodes, then quickly umount and mount. for i in $(seq 0 500) do dd if=/dev/zero of="/mnt/foo/$i" bs=1M count=1 done umount /mnt/foo& mount /mnt/foo does the trick for me. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: drop stale reference to volume_mutexAnand Jain1-4/+3
Commit dccdb07bc996 ("btrfs: kill btrfs_fs_info::volume_mutex") removed the last use of the volume_mutex, forgetting to update the comment. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: free alien device after device addAnand Jain1-1/+11
When an old device has new fsid through 'btrfs device add -f <dev>' our fs_devices list has an alien device in one of the fs_devices lists. By having an alien device in fs_devices, we have two issues so far 1. missing device does not not show as missing in the userland 2. degraded mount will fail Both issues are caused by the fact that there's an alien device in the fs_devices list. (Alien means that it does not belong to the filesystem, identified by fsid, or does not contain btrfs filesystem at all, eg. due to overwrite). A device can be scanned/added through the control device ioctls SCAN_DEV, DEVICES_READY or by ADD_DEV. And device coming through the control device is checked against the all other devices in the lists, but this was not the case for ADD_DEV. This patch fixes both issues above by removing the alien device. CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: include non-missing as a qualifier for the latest_bdevAnand Jain1-0/+2
btrfs_free_extra_devids() updates fs_devices::latest_bdev to point to the bdev with greatest device::generation number. For a typical-missing device the generation number is zero so fs_devices::latest_bdev will never point to it. But if the missing device is due to alienation [1], then device::generation is not zero and if it is greater or equal to the rest of device generations in the list, then fs_devices::latest_bdev ends up pointing to the missing device and reports the error like [2]. [1] We maintain devices of a fsid (as in fs_device::fsid) in the fs_devices::devices list, a device is considered as an alien device if its fsid does not match with the fs_device::fsid Consider a working filesystem with raid1: $ mkfs.btrfs -f -d raid1 -m raid1 /dev/sda /dev/sdb $ mount /dev/sda /mnt-raid1 $ umount /mnt-raid1 While mnt-raid1 was unmounted the user force-adds one of its devices to another btrfs filesystem: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt-single $ btrfs dev add -f /dev/sda /mnt-single Now the original mnt-raid1 fails to mount in degraded mode, because fs_devices::latest_bdev is pointing to the alien device. $ mount -o degraded /dev/sdb /mnt-raid1 [2] mount: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. kernel: BTRFS warning (device sdb): devid 1 uuid 072a0192-675b-4d5a-8640-a5cf2b2c704d is missing kernel: BTRFS error (device sdb): failed to read devices kernel: BTRFS error (device sdb): open_ctree failed Fix the root cause by checking if the device is not missing before it can be considered for the fs_devices::latest_bdev. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: drop useless goto in open_fs_devicesAnand Jain1-7/+5
There is no need of goto out in open_fs_devices() as there is nothing special done there. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: make btrfs_read_disk_super return struct btrfs_disk_superNikolay Borisov1-24/+23
Instead of returning both the page and the super block structure, make btrfs_read_disk_super just return a pointer to struct btrfs_disk_super. As a result the function signature is simplified. Also, read_cache_page_gfp can never return NULL so check its return value only for IS_ERR. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: relocation: add error injection points for cancelling balanceQu Wenruo1-1/+1
Introduce a new error injection point, should_cancel_balance(). It's just a wrapper of atomic_read(&fs_info->balance_cancel_req), but allows us to override the return value. Currently there are only one locations using this function: - btrfs_balance() It checks cancel before each block group. There are other locations checking fs_info->balance_cancel_req, but they are not used as an indicator to exit, so there is no need to use the wrapper. But there will be more locations coming, and some locations can cause kernel panic if not handled properly. So introduce this error injection to provide better test interface. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: balance: factor out convert profile validationDavid Sterba1-24/+21
The validation follows the same steps for all three block group types, the existing helper validate_convert_profile can be enhanced and do more of the common things. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: Rename __btrfs_alloc_chunk to btrfs_alloc_chunkNikolay Borisov1-25/+13
Having btrfs_alloc_chunk doesn't bring any value since it encapsulates a lockdep assert and a call to find_next_chunk. Simply rename the internal __btrfs_alloc_chunk function to the public one and remove it's 2nd parameter as all callers always pass the return value of find_next_chunk. Finally, migrate the call to lockdep_assert_held so as to not lose the check. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: parameterize dev_extent_min for chunk allocationNaohiro Aota1-4/+5
Currently, we ignore a device whose available space is less than "BTRFS_STRIPE_LEN * dev_stripes". This is a lower limit for current allocation policy (to maximize the number of stripes). This commit parameterizes dev_extent_min, so that other policies can set their own lower limitat to ignore a device with insufficient space. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: factor out create_chunk()Naohiro Aota1-61/+71
Factor out create_chunk() from __btrfs_alloc_chunk(). This function finally creates a chunk. There is no functional changes. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: factor out decide_stripe_size()Naohiro Aota1-58/+78
Factor out decide_stripe_size() from __btrfs_alloc_chunk(). This function calculates the actual stripe size to allocate. decide_stripe_size() handles the common case to round down the 'ndevs' to 'devs_increment' and check the upper and lower limitation of 'ndevs'. decide_stripe_size_regular() decides the size of a stripe and the size of a chunk. The policy is to maximize the number of stripes. This commit has no functional changes. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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